Traction-wheel.



D. W. MCLAUGHLIN.

TRACTION WHEEL.

ITION FILED MAYZ APPLIC I 1,1 90,1 83. Patented July 4, 1916.

UMTED STATES PATENT OFFICE.

DENNIS W. MOLAUGHLIN, OF BERKELEY, CALIFORNIA.

, TRACTION-WHEEL.

Specification of Letters Patent.

' Patented July 4, 1916.

Application filed May 26, 1913. Serial No. 769,832.

for tractors, particularly in soft ground: to

increase the traction efliciency without Sacrificing. the supporting qualities of the wheel tread; to produce a wheel tread that will sustain the weight of the tractor on a fin. ished road surface, without injury to the road surface and retain the maximum tractive efficiency on hard or soft ground; to produce a self cleaning tread neat in appearance, cheap in manufacture, and preferabl composed of an integral whole.

Other objects and advantages will appear as the invention is disclosed in the following description devoted to ,the preferred form for putting this invention into practice. y

The invention possesses other advantageous features which with the foregoing, will be set forth at length in the following description, where I shall outline in full that form of invention selected for illustration in the drawings accompanying and forming part of the present specification. The novelty of the invention will be included in the claims succeeding said description. From this, it will be apparent that I do not restrict myself to the showing made by said drawings and description, as I may adopt many variations within the scope of'my invention as expressed in said claims.

In small tractors ranging in weight from a ton upward, the weight is not suflicient to give the necessary tractive efficiency on a plain tread, particularly in soft ground such as fields in cultivation. The use of growsers or the like on the tread is prohibitive because of the injury such aids to traction do to road surfaces. A tread constructed in accordance with this invention will give the maximum tractive efliciency under all consistent soil conditions, without marring road surfaces or sinking deeply into loose or soft ground.

In the drawings: Figure l is a side elevation of a tractor wheel constructed in accordance with this invention, a portion of the wheel tread being broken away. Fig. 2 is a front elevation of the same, partially in cross'section to disclose the conformation of the web of the tread. Fig. 3 is a peripheral cross section taken on the line III-III looking toward the hub of the wheel. Fig.

4 is a fragmentary detail in vertical cross v section on the line IV-IV.

The circumferential line of the wheel is preferably truly concentric with the hub, while the line of the tread zig zags back and forth across the plane line 4 of the tread, presenting the angular transverse edges 5 to the ground in succession. The point of conjunction of the'edges 5 form the apex of open triangles, alternately facing in opposite directions; from each apex is extended a lateral plane, the edge 6 of which converts each open triangle intoa Y shape. The visible track left by this tread shows a series of alternately reversed Ys. The lateral plane of the tread from 7 to 8 is an arc with its radial-center approximately in the axis of the wheel; although this sweep of the arc is not arbitrary and should vary with the load, tractive duty, surface conditions, etc., affecting the Wheel specifications. This lateral arc of the tread shows the tail 6 of the Y to be elevated above the road plane.

On'a very hard surface such as asphalt or concrete roads, onlythe extreme periphery of the wheel will be in contact, this will confine the tractive effort to the V of the open triangle; in proportion as the tread sinks into a softer surface more tractive and more supporting area will come into play. The

supporting power of the tread, in addition to the tractive elements previously described, a series of peculiarly interrelated and combined inclined triangular planes are interposed between the circumferential edge and the rim of the wheel. For many and obvious reasons it is desirable that both sides of the wheel be identical and that the wheel be equally efficient rotating in either direction.

To preserve uniform cross section, as nearly as may be, throughout the web of the tread portion of the wheel for the sake of symmetry, economy in the use of material, and ease in molding, the inclined triangular planes 10, 11, and 12 should be arranged substantially as shown; although variations to suit special demands will suggest themselves to those skilled in this art, in putting this invention into practice. The angles of the planes 6, 10, ll andl2 all incline toward the rim of the wheel, thereby presenting resistance to the sinking of the wheel into the soft ground by exerting a lateral packing pressure against that portion of the ground in contact with these planes on the-ground portion of the wheel; furthermore this peculiar arrangement of angles reduces the tendency of the wheel to lift the ground in leaving it, while having the opposite tendency in entering. In soft sticky land adhesion might be suflicient to cause the tread to lift out a section equal to the space between the planes 6 a very serious objection, unless the structure of the tread had inherent tendencies to dislodge such an obstruction. A valuable feature of this invention is this inherent tendency to disgorge obstructions in the tread. A section of mud sufliciently adhesive to be carried over would be dislodged when it came in contact with the ground in front of the wheel; this is caused by the wedging action of the inside of the plane 11; as the apex of the section of mud is forced up the incline, contact is broken between the planes 10 and 12, and there being no lateral resistance between the planes 6 the obstruction is forced free of the tread as the latter sinks into the ground. Normally the wheel is the moving object and the ground stationary, in the case of the obstruction the positions are reversed and the most powerful principle in mechanics, the wedge, is brought to bear against the obstruction. In simple terms the tread is a series of wedges entering the ground against its lateral resistance; in contradistinction to that class of treads presenting a superficial area to the ground on a plane parallel to the plane of the ground surface.

Believing this description to be complete, correct and sufiicient for those competent to put this invention into practice, what I claim and desire to secure by Letters Patent is:

1. A traction wheel having a narrow rim, a tread including oppositely open triangles formed by the base lines of inclined triangular planes, having their apices in said rim; and inverted triangular planes whose base line extends between said apices, and whose apex joins the contiguous apex of said open triangles.

2. A traction wheel having a narrow rim, a tread including oppositely open triangles formed by the base lines of inclined triangular planes having their apices in said rim, and joined by a triangular plane whose base line extends between said apices, and whose apex joins the contiguous apex of said open triangles; and radial planes extending laterally from said apices.

3. A traction wheel having a narrow rim, inclined planes extending from said rim to form substantially triangular, pyramidal, open spaces on opposite sides of said wheel, and radial planes extending laterally from the apices of said triangular spaces, whereby the peripheral tread of the wheel presents a series of conjoined Y shaped lines facing in alternately opposite directions.

4. A traction wheel having a narrow rim and a zig-zag tread, inclined planes extending from said rim to said tread to form polygonal spaces on alternately opposite sides of said wheel, and radial planes extending laterally from alternate sides of said tread.

5. A traction wheel having a narrow rim and a zig-zag tread wider than said rim; radial planes extending from said tread to said rim; radial planes extending laterally beyond said tread presents a series of conjoined Y shaped lines open in alternately opposite directions.

6. A traction wheel having a narrow rim, and a tread wherein the periphery presents a series of conjoined Y shaped lines open in alternately opposite directions; and radial planes extending from saidtread to said In testimony whereof, I have hereunto set 10 rim. my hand at San Francisco, this 9th day of 7. Adtraction wfileel having a nargow rim; May, 1913. a trea wider vt an said rim an spaced 5 therefrom, and planes interposed between DENNIS MGLAUGHLIN said rim and said tread, whereby the pe- In presence of riphery of the tread presents a series of BALDWIN VALE, conjoined Y shaped lines open in alternately THEO. LARsEN,

opposite directions. GENEVIEVE S. DONELIN. 

